/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.amphiprion.gameengine3d.util;

import java.nio.FloatBuffer;
import java.nio.IntBuffer;

import android.opengl.Matrix;

/**
 * A matrix stack, similar to OpenGL ES's internal matrix stack.
 */
public class MatrixStack {
	public MatrixStack() {
		commonInit(DEFAULT_MAX_DEPTH);
	}

	public MatrixStack(int maxDepth) {
		commonInit(maxDepth);
	}

	private void commonInit(int maxDepth) {
		mMatrix = new float[maxDepth * MATRIX_SIZE];
		mTemp = new float[MATRIX_SIZE * 2];
		glLoadIdentity();
	}

	public void glFrustumf(float left, float right, float bottom, float top, float near, float far) {
		Matrix.frustumM(mMatrix, mTop, left, right, bottom, top, near, far);
	}

	public void glFrustumx(int left, int right, int bottom, int top, int near, int far) {
		glFrustumf(fixedToFloat(left), fixedToFloat(right), fixedToFloat(bottom), fixedToFloat(top), fixedToFloat(near), fixedToFloat(far));
	}

	public void glLoadIdentity() {
		Matrix.setIdentityM(mMatrix, mTop);
	}

	public void glLoadMatrixf(float[] m, int offset) {
		System.arraycopy(m, offset, mMatrix, mTop, MATRIX_SIZE);
	}

	public void glLoadMatrixf(FloatBuffer m) {
		m.get(mMatrix, mTop, MATRIX_SIZE);
	}

	public void glLoadMatrixx(int[] m, int offset) {
		for (int i = 0; i < MATRIX_SIZE; i++) {
			mMatrix[mTop + i] = fixedToFloat(m[offset + i]);
		}
	}

	public void glLoadMatrixx(IntBuffer m) {
		for (int i = 0; i < MATRIX_SIZE; i++) {
			mMatrix[mTop + i] = fixedToFloat(m.get());
		}
	}

	public void glMultMatrixf(float[] m, int offset) {
		System.arraycopy(mMatrix, mTop, mTemp, 0, MATRIX_SIZE);
		Matrix.multiplyMM(mMatrix, mTop, mTemp, 0, m, offset);
	}

	public void glMultMatrixf(FloatBuffer m) {
		m.get(mTemp, MATRIX_SIZE, MATRIX_SIZE);
		glMultMatrixf(mTemp, MATRIX_SIZE);
	}

	public void glMultMatrixx(int[] m, int offset) {
		for (int i = 0; i < MATRIX_SIZE; i++) {
			mTemp[MATRIX_SIZE + i] = fixedToFloat(m[offset + i]);
		}
		glMultMatrixf(mTemp, MATRIX_SIZE);
	}

	public void glMultMatrixx(IntBuffer m) {
		for (int i = 0; i < MATRIX_SIZE; i++) {
			mTemp[MATRIX_SIZE + i] = fixedToFloat(m.get());
		}
		glMultMatrixf(mTemp, MATRIX_SIZE);
	}

	public void glOrthof(float left, float right, float bottom, float top, float near, float far) {
		Matrix.orthoM(mMatrix, mTop, left, right, bottom, top, near, far);
	}

	public void glOrthox(int left, int right, int bottom, int top, int near, int far) {
		glOrthof(fixedToFloat(left), fixedToFloat(right), fixedToFloat(bottom), fixedToFloat(top), fixedToFloat(near), fixedToFloat(far));
	}

	public void glPopMatrix() {
		preflight_adjust(-1);
		adjust(-1);
	}

	public void glPushMatrix() {
		preflight_adjust(1);
		System.arraycopy(mMatrix, mTop, mMatrix, mTop + MATRIX_SIZE, MATRIX_SIZE);
		adjust(1);
	}

	public void glRotatef(float angle, float x, float y, float z) {
		Matrix.setRotateM(mTemp, 0, angle, x, y, z);
		System.arraycopy(mMatrix, mTop, mTemp, MATRIX_SIZE, MATRIX_SIZE);
		Matrix.multiplyMM(mMatrix, mTop, mTemp, MATRIX_SIZE, mTemp, 0);
	}

	public void glRotatex(int angle, int x, int y, int z) {
		glRotatef(angle, fixedToFloat(x), fixedToFloat(y), fixedToFloat(z));
	}

	public void glScalef(float x, float y, float z) {
		Matrix.scaleM(mMatrix, mTop, x, y, z);
	}

	public void glScalex(int x, int y, int z) {
		glScalef(fixedToFloat(x), fixedToFloat(y), fixedToFloat(z));
	}

	public void glTranslatef(float x, float y, float z) {
		Matrix.translateM(mMatrix, mTop, x, y, z);
	}

	public void glTranslatex(int x, int y, int z) {
		glTranslatef(fixedToFloat(x), fixedToFloat(y), fixedToFloat(z));
	}

	public void getMatrix(float[] dest, int offset) {
		System.arraycopy(mMatrix, mTop, dest, offset, MATRIX_SIZE);
	}

	private float fixedToFloat(int x) {
		return x * 1.0f / 65536.0f;
	}

	private void preflight_adjust(int dir) {
		int newTop = mTop + dir * MATRIX_SIZE;
		if (newTop < 0) {
			throw new IllegalArgumentException("stack underflow");
		}
		if (newTop + MATRIX_SIZE > mMatrix.length) {
			throw new IllegalArgumentException("stack overflow");
		}
	}

	private void adjust(int dir) {
		mTop += dir * MATRIX_SIZE;
	}

	private final static int DEFAULT_MAX_DEPTH = 32;
	private final static int MATRIX_SIZE = 16;
	private float[] mMatrix;
	private int mTop;
	private float[] mTemp;
}
